This invention relates to an energy absorbing bumper assembly and more particularly to an energy absorbing bumper assembly for vehicles. The energy absorbing bumper assembly renders the vehicle more safe by absorbing and distributing energy upon impact of the vehicle bumper with a foreign object.
Because of the concern regarding the protection afforded to automobile occupants and vehicle body structure by bumper assemblies, the United States Congress has passed federal safety standards setting forth requirements for the impact resistance and configuration of front and rear vehicle surfaces. In particular, the vehicle surface must pass the center pendulum and low-engagement pendulum impact tests. These standards require that the vehicle be able to sustain a number of specified impacts at various positions along the bumper assemblies thereof. Broadly, requirements are such that the bumper assembly must sustain specified frontal impacts and must sustain specified impacts at the ends or corners thereof.
As shown in U.S. Pat. No. 3,866,963 granted Feb. 18, 1975 in the name of Peter A. Weller, energy absorbing blocks of an elastomeric material have been disposed between a shell and a mounting means of a bumper assembly at the assembly's corners and frontal face. When these blocks are partially contacted by an impacting device, the elastomeric material in the impact zone tends to bulge into the adjacent uncompressed elastomeric material. This characteristic can result in a force being generated normal or perpendicular to the impacting device. Furthermore, this characteristic can also result in loading of the energy absorbing block in shear and a lifting of the vehicle. To minimize this undesirable lifting characteristic of the block, an anti-lift feature in the form of a cored-out area adjacent the impact zone is provided by the present invention.
This invention also provides an energy absorbing bumper assembly having a configuration particularly suitable for meeting current specified impact requirements as well as meeting practical requirements.
An energy absorbing bumper assembly constructed in accordance with this invention includes a mounting means adapted for attachment to a vehicle and an elongated shell disposed adjacent the mounting means with first bumper means for absorbing a first quantity of energy disposed between the shell and the mounting means. The first bumper means includes a plurality of block pairs spaced apart, each block pair comprising first and second members spaced vertically apart and defining a cavity adjacent a front face of the shell. A second bumper means is disposed within the cavity of the block pairs. The second bumper means has a different energy absorbing capacity than the first bumper means and the second bumper means absorbs a second quantity of energy.